Book excerpt: High school geometry teacher, Donna Russell likes her life well-ordered and logical, even if it is a tad solitary at times. But when a charming co-worker at the local food bank disappears just before Christmas, Donna is left with more questions than solutions. After the missing man's neighbor, muscle-bound EMT Sam Holton, volunteers as Donna's crime-fighting sidekick, sparks fly between them. Donna wonders if Sam can be trusted, or if he's trying to throw an unknown into her calculations—and her life. And when police recover a body from the icy Niagara River, Donna is faced with the most frustrating equation of all: can murder plus mayhem ever equal romance?